Check the sub folders.. find out which folder is occupying more space...
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If live update folder is large there might be some currupt definition. you can clear them.
REF:
http://service1.symantec.com/SUPPORT/ent-security.nsf/docid/2007123111551948
https://www-secure.symantec.com/connect/articles/how-clear-corrupt-virus-definitions-sepm
https://www-secure.symantec.com/connect/forums/machines-stopping-because-disk-full
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If content folder is large, then you can reduce the number of content to keep under sepm console.
Login toSEPM--> Admin---> Servers---> Local site properties--->Live update settings--->Disk space management for download.
Reduce the number of content as per ur need... (This will delete the some data from inetpub\content folder)
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If you are using embedded database you can shrink the database.
REF:
http://service1.symantec.com/SUPPORT/ent-security.nsf/815a8fe58decda8488257363002b62ab/64ab2040ab6d71a7882573fc0000f8a2?OpenDocument
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If you are using Local MS SQL database then sem5 database files can be moved.(If installed in C drive).
Stop SEPM service.
Login to MS SQL management studio.
Detach the SEM5 database.
Move the SEM5 related files under "Program Files\Microsoft SQL Server\MSSQL.1\MSSQL\Data" folder to disk where there sufficient disk space.
attach the database in management console using sem5.mdf file in other disk.
Start the SEPM service.
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